Fracture Water Treatment Method and System

ABSTRACT

A method and system for treatment of flow-back and produced water from a hydrocarbon well in which fracturing operations are carried out using a phase separation and creating of positive charge in the water.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.13/832,759, filed Mar. 15, 2013, which is a continuation in part of U.S.application Ser. No. 13/594,497 filed Aug. 24, 2012, which claimspriority to U.S. Provisional App. No. 61/676,628, filed Jul. 27, 2012.This application claims priority to all the previously listedapplications and also claims priority to U.S. Divisional ApplicationSer. No. 13/753,310, filed on Jan. 29, 2013.

BACKGROUND OF THE INVENTION

This invention concerns the apparatus and processing steps for treatingthe flow-back and produced water and the other constituents that areused to hydraulically cause the creation of channels or fractures orfissures in hydrocarbon wells (for example, deep oil-shale deposits).

Over the centuries, people have tried different ways to take advantageof and use the inherent qualities of naturally-occurring hydrocarboncompounds to enhance his life style and cope with the many challenges ofexistence. For over two thousand years, the “Burning Sands” of Kirkuk,in Iraq, provided heat to Kurdish tribes, which came from the methanegas that seeped upwards from deep Geological formations to the Earth'ssurface only to be ignited and burn continuously to this day. Also thesurface seepages of crude oil, in Pennsylvania and California, were usedby the American Indians to water-proof the canoes that they used intraveling on the waterways of North America. These are only two earlyexamples of man's utilization of natural gas and crude oil to improvehis way of life.

Drake's successful drilling of a shallow crude oil well in Pennsylvania,in the late Nineteenth Century, marked the beginning of man's greatestperiod of economic growth driven, in great measure, by the rapid stridesthat were made in the exploration, production, and refining, ofnaturally-occurring gaseous and liquid hydrocarbon compounds. They arenow used for transportation fuels, power generation, lubricants,petrochemicals, and the many thousands of other products andapplications that we use in our daily lives today. The birth anddevelopment of what we now call “the Oil Industry” is one of the majorprincipal factors and enabling driving forces contributing to theestablishment and spectacular growth in the world's economy. This periodof economic development is known as “The Industrial Revolution.”

During this period, many new oil fields were discovered in many parts ofthe world and the growth in the demand for crude oil and petroleumproducts grew at a fantastic rate due to the many new uses forpetroleum-derived products that continued to be discovered well into theTwenty-First Century. Throughout this period the Oil Industry found manyoil new fields or large deposits or reservoirs of conventionally varyinghydrocarbon mixtures of liquid and gaseous compounds (both on land andoffshore in the various bodies of water throughout the world). At thesame time, the Industry also discovered the existence of largequantities of heavy and light hydrocarbon compound mixtures that werenonconventional in structure and were so enmeshed in the complexmaterial matrixes that the hydrocarbon molecule compounds containedtherein could not be extracted economically.

These nonconventional hydrocarbon compound sources fall into twodistinctly different categories. Firstly there are the “heavy” orlong-chain hydrocarbon molecule compounds such as the oil sands depositsin Canada and the heavy oil deposits in the Kern River or Bellridgeregions of California or in the heavy oil belt of the Orinoco riverdelta region in Venezuela or the Mayan oil in Mexico where the heavy oilproduced was extremely viscous and was in a semi-solid state at ambienttemperatures. In these cases pour point or viscosity reduction was ofprimary importance. Secondly there are the “light” or “short-chain”hydrocarbon molecule compounds that are entrapped in various shaledeposits throughout the United States and in many other areas in theworld.

In certain countries of the world, namely in Spain, Estonia and Brazilthere are large, but shallow, oil shale deposits where those countriesdid not have large reserves or deposits of conventional crude oil.There, a “brute force” method for the extraction of shale oil or kerogenwas carried out by heating the shale rock in high temperaturepressurized retorts. This practice was started as early as the nineteentwenties. The extracted kerogen or shale oil fuel was then burned infurnaces for heating purposes as well as a transportation fuel fordiesel and other internal combustion engines. The extracted kerogen fuelhad about the same b.t.u. fuel value and combustion characteristics asregular-grade gasoline or petrol as produced from conventional crude oilrefining facilities. Those countries also did not have the necessaryamount of hard currency or United States Dollars to buy conventionalcrude oil on the international commodities market but they did havelarge volumes of shale rock (although the amount of shale oil or Kerogenextracted from these shale deposits was less than four percent by weightof the shale rock itself, leaving about ninety five percent of the shalerock as waste materials). The hot condensable hydrocarbon compounds wereliquefied in a conventional condensing heat exchanger unit and becamethe kerogen fuel. The non-condensable hydrocarbons, mainly methane, wereflared or just released into the atmosphere. All these short-chain orlight hydrocarbon compounds are trapped or sealed within the oil shalematerial matrix structure and when heated, under pressure, they arereleased or liberated from this matrix in a gaseous phase.

In the United States, there are many areas where oil shale rock depositsare to be found, but most of them are located as deep deposits five toten thousand feet below the surface of the earth. As early as before thenineteen twenties, many attempts made to mine or extract the kerogen oilfrom stratified shale formations. Although the shale oil proved to be avery suitable hydrocarbon product, its cost of production was well inexcess of the market price of similar products; thus this situationproved to be uneconomical. Additional development and investment was notjustified at that time.

All of these factors and conditions have changed dramatically over thepast years due, primarily, to the rapid development and exploitation oftwo specialized technologies. The first of these is the carefullycontrolled and steerable directional drilling techniques that allowedrigs to be able to initially drill vertically and then be controlled orsteered to rotate into a horizontal position while drilling to apre-determined depth. The drilling could then continue to drill wellbores horizontally in the shale formation for a considerable distance.The second most important technological development was the applicationof an old process, namely the practice of hydraulically fracturing oldervertical oil wells in order to increase the flow rate as well as topromote the further stimulation of the older, oil wells and therebyextend the economic life of the depleting oil fields.

Over the years many different techniques were developed and implementedin an attempt to extend the productive life of older oil and more matureoil field fields. Water flooding was one of the practices that wasemployed to maintain reservoir pool pressure in depleting oil fields aswell as the injection of pressurized methane gas (when available and notbeing flared) in order to achieve the same result. Another techniquethat was tried was the use of “Shaped Charges” of explosives that werestrategically placed in well casings so they could be detonated in thepay zone areas in the well bore and the force of these explosionspenetrated the wall of the casing and caused fractures or fissures to beopened.

Such methods for EOR (Enhanced Oil Recovery) were the oil industry normfor many years. However some oil companies were concerned about thedangers in using explosives as a means of extending the productive lifeof depleting oil fields; and, in the late nineteen forties, the practiceof using highly-pressured water and sand mixtures to produce fissures orfractures in the pay-zone areas began. This technique was developed totry to increase the rate of flow in the oil well and also to extend theproductive life of a mature and depleting oil field without the use ofexplosives. Opening new channels hydraulically in the older pay zonesmade it easier for the liquid and gaseous hydrocarbons to flow freelyunder bottom hole pressure up to the surface for collection as crude oiland gas products.

Also the practice of using work-over rigs to clean out old oil wellcasings that had restricted hydrocarbon flows due to the accumulation ofasphaltic or paraffinic compounds was wide-spread during this period.

The use of all these types of oil well stimulation practices, as well asthe use of other enhanced oil recovery techniques, continued over a longperiod of time and many improvements were developed over the years. Oneof these improvements was the development of the larger capacity andmore powerful barite mud pumps that were needed to assist in thedrilling of deeper and deeper oil wells, both onshore as well asoffshore. Some of these oil wells were drilled in water depths exceedingeight thousand feet; further drilling depths adding more than twentythousand feet, and thus there was a need to enlarge the capacity andincrease the pressure capability level of the hydraulic fracturing pumpsas well.

The discovery of a number of large deposits of oil shale formations,plus the newly developed technologies of steerable directional drillingcapabilities, coupled with the ability to use highly pressurizedhydraulic fracturing equipment, allowed the industry to proceed withthese new fracturing techniques. They were able to directionally drill,both vertically and horizontally, in the deep shale formations and thenhydraulically fracture the formation to release the gaseous and liquidhydrocarbons that were contained in the shale matrix materialformations.

These new technologies have caused an economic “sea change” in how theworld now values liquid and gaseous hydrocarbons in the global energycommodities market.

However, during the period when the application of hydraulic fracturingwas becoming more wide spread, its growth, technologically andoperationally, was carried out in a very haphazard, hit and miss, ad hocmanner. Many of the improvements that were made were the result ofunscientifically developed trial and error attempts to improve the rateof production in an oil well as well as trying to extend the economiclife of established oil fields. This was all done without the benefit offully examining or understanding the sound scientific reasons behind theneed for those improvements. The best example of this unscientificapproach, in trying to solve specific processing problems, is what wasoccurring in the proper selection and use of various types of proppantsin the hydraulic fracturing process.

After the initial pressurized water fracturing is accomplished, strongproppant materials need to remain in the fissures or fractures that areproduced by the pressurized water technique if the desired increase inthe flow rate of the produced hydrocarbons is to be achieved. Proppantsare the selected means of “propping up” the new openings or cracks inthe formations, so that they will continue to keep the new fractures orfissures open and to allow the hydrocarbon compounds to flow freely intothe well bores so they can be discharged through the well head's controlequipment.

Without the proper proppants that are strong enough and correctly sizedto keep the fissures continuously open, the well's production rate willdecline rapidly as proppant fines and softer material particles fill upthe fissures. These will decrease the rate of flow and ultimately blockthe flow of hydrocarbons into the well bore. Many types of sands havingdifferent compositions, shapes and sizes were tested as well as manyother types of proppant materials such as aluminum oxides, etc.

The key issue here is that the proper proppant that should be used in ahydraulic fracturing process is the single most important factor that isneeded in achieving and maintaining the proper “voids ratio” that isneeded in the pressurized water fractured channels to be able to realizethe full benefit of the hydraulic fracturing process.

While these considerations are important in hydraulic fracturing invertically drilled oil wells with selected pay zones, they are far morecritical and important when applying the hydraulic fracturing process inhorizontally-layered oil shale formations. As a result of the magnitudeof the “Shale Gas Revolution” we are now just starting to learn more andunderstand more about the nature and characteristics of the varioustypes of shale formations.

Oil shale is a form of sedimentary deposits that were laid down eons agoin the form mainly of calcium carbonates, sodium carbonates, calciumbicarbonates, quartz as well as soil materials and other compounds thatbecame entrapped in the matrix of materials as these oil shales werebeing formed and ultimately deposited in the shale formations that weknow about today. Many oil shale formations cross tectonic fault linesin the crust of the earth and thus can be discontinuous in theirconfiguration. Some oil shale formations are slightly inclined in boththe vertical and horizontal planes. As a result, wire line tracking aswell as three dimensional seismic analyses becomes an important part ofthe shale gas exploration and development process.

Retrospectively it is important to recognize and stress the criticalfunction that properly structured and sized proppants perform for theoptimum extraction and production of gaseous and liquid hydrocarboncompounds which are the product as a result of the hydraulic fracturingof an oil shale deposit. This fact was not fully understood orappreciated, in the oil industry, until early in the twenty-firstcentury. By the end of the twentieth century the Petroleum Industry hadalready been using the technique of hydraulic fracturing for enhancedoil recovery and oil well stimulation on producing wells for more thanfifty years. All of the hydraulic fracturing operations that werecarried out before the turn of the twenty first century were designed toextend the productive life of existing vertically drilled oil wells orachieve greater hydrocarbon flow rates for completed wells. All of thesehydraulic fracturing operations were carried out in vertically-drilledoil wells and were fracturing pay zones that were essentially sand incomposition, and were producing flowing liquid or gaseous hydrocarbonsunder bottom hole temperature and pressure conditions. All were in sandformations that had relatively high permeability and porosity values orgood voids-ratio characteristics.

With the introduction of steerable vertical and horizontal drillingequipment together with very high pressure fracturing pumps (called bysome “intensifiers”), the oil industry then applied the same hydraulicfracturing techniques that had been successfully developed and used invertical oil well hydraulic fracturing operations and applied these sameprocedures to the well bores that were horizontally drilled in the deepshale formations but with less than satisfactory results. Some of theoil shale formations were more productive than others and a large numberof approaches were attempted in order to try to increase the amount ofencapsulated hydrocarbons that were released by hydraulic fracturing.Chemicals were added to try to control the growth of the water bornemicroorganisms that were impeding the flow of hydrocarbons, chemicalswere also added in order to control corrosion and encrustations. Surfacetension reducing chemicals were also added to try to make the fracturingwater more capable of penetrating the fissures that were created by thehighly pressured water. Some combination of steps were more successfulin one area of oil shale than the same steps being taken and applied inanother oil shale formation particularly in the difference in thepercentage or amount of hydrocarbon product that was ultimately beingextracted from a specific amount of hydrocarbon content in a given oilshale deposit.

It was not until the industry started to realize that the traditionalprinciples of petroleum technology were not fully applicable to thenewly developed attempts to extract entrapped liquid and gaseoushydrocarbons from mineral rock formations that did allow them to flowfreely even in deep high temperature and high pressure locations.Petroleum engineers then turned to the principles of applying theexamination of hard rock mechanics of minerals geology criteria inseeking a comprehensive analysis and understandable answer to theseissues. Recently, research efforts proved that all shale formationscould be categorized and could be roughly divided in to two distinctmeasurable and identifiable classifications being either a “soft shale”or a “hard shale.” See, e.g. Denney, Dennis. (2012 March).Fracturing-Fluid Effects on Shale and Proppant Embedment. JPT. pp.59-61.The test criteria are based upon the principle of measuring thestress/strain or Young's Modulus value of a given material both beforeand after fracturing. The test measures the nano indentation of amineral after applying a specific stress level. Hard shales recorded lownano indentation values while the soft shales tested measured higherindentation values. The hard shales had mainly silica, calciumcarbonates, calcites, and quartz in their composition along withcolloidal clays; whereas the soft shales had sodium bicarbonates,nahcolites and colloidal clay components.

The ability to accurately determine the true mineral characteristics ofan oil shale is very important in selecting the best operationaltechniques that are needed in order to optimize or maximize the ultimaterecovery of hydrocarbon components from a specific shale formation ordeposit. Soft oil shale formations respond differently from hard oilshale formations after both have been subjected to the same level ofhydraulic water pressure for the same soaking period of time. Hard oilshales, under high hydraulic pressures yield fissures or channels thatare relatively short in penetration length and rather small in the crosssectional diameters of their fissures or flow channels. Soft oil shales,on the other hand, under the same high hydraulic pressure and soakingperiod yield fissures that are of greater length and have crosssectional diameters that are relatively larger than what can be achievedfrom the hydraulic fracturing of materials in the hard oil shaleformations.

Aside from controlling the growth of microorganisms and the preventionof scale encrustations and “slick” water provisions, the most importantfactor in an operation's ability to extract the maximum or optimumamount of hydrocarbon from a given shale formation is the selection ofthe proper size and type of proppant that is carried into the fracturezone by the fracturing water. If the shale to be fractured is a hardshale the proppant must be of small enough size so that it can becarried into the small diameter fissures that are the result of the hardshale fracturing operation and strong enough to be able to keep thechannel or fissure open long enough in order to allow the containedliquid or gaseous hydrocarbon product to flow freely horizontally andvertically in the well bore so as to be recoverable after being releasedto the surface facilities. If the proppant used is too large for thesmall diameter size fissure, the proppant will not penetrate into thefissure and remain there in order to keep the fissure channel open, andthe amount of recoverable produced hydrocarbons will be significantlyreduced. Alternatively, if an operation is hydraulic fracturing in asoft shale formation the properly sized proppant should be larger indiameter than the proppant that would be suitable for use in a hardshale. This will allow the proppant to be carried into the largerdiameter fissures that are the result of the hydraulic fracturing of asoft shale. A smaller size proppant would not be as effective and thiswould result in a significant reduction in the amount of hydrocarbonproduct that could be produced.

Now that we have more scientifically measureable data regarding thedifferences in the various types of oil shale formations the industrynow realizes, more clearly, the economic importance of selecting theproper proppant for the hydraulic fracturing of various types of oilshale formations. The best proppant for hydraulically fracturing softmineral shales we now know is different from the best proppant that weneed to use when hydraulically fracturing a hard mineral shale. Thus,there is a need for specific proppants for specific oil shales.

An object of examples of the invention, therefore, is to provide a widerange of properly sized and constituted proppants using virtually allthe slurry materials that are carried to the surface and are containedin the flow-back water stream from the hydraulic fracturing of gas andoil formations.

As a result of the rapid increase in the extent and amount of hydraulicfracturing of oil shale deposits being developed in a number ofdifferent areas in the United States, there has arisen a number ofecological and environmental concerns that must be addressed if theindustry is to grow successfully. For instance toxic chemicals (such asglutaraldehyde) are used as a biocide to kill, control, or eliminate,the water borne micro-organisms that are present in the water used inthe hydraulic fracturing process. There is great concern such toxicchemical-bearing fracturing water could migrate into a potable wateraquifer. Also of concern is the possibility of friction-reducingchemicals (e.g., polyacrylamide) or scale inhibitors (e.g., phosphonate)finding their way into and contaminating an aquifer. Detergent soapmixtures as well as chemicals such as potassium chloride are commonlyused as surface-tension-reducing surfactants and could create publichealth issues. The current practice of injecting brine-contaminatedflow-back water into disposal wells is another of concern to the public.

In some examples of traditional fracturing jobs, after explosivelyperforating a horizontal well casing, a water mixture is injected athigh pressure into a multitude of individually sequenced fracturingzones, each being sealed off at both ends by packer sleeves. This allowsthe water mixture to remain in the shale formation under pressure forseveral days, creating channels, fractures, or fissures which, when thehydraulic pressure is released by a coiled drilling operation, allowhydrocarbon gas and liquid elements to have passageways that allow flowto the surface. For each individual fracturing zone, the pressure in thewater mixture is reduced in sequence so that the depressurized waterflows back horizontally into the well bore and then proceeds upward inthe vertical cemented well section to the ground surface elevation. Muchof the proppant remains behind in these channels; however, a significantamount comes out in the back-flow water.

The flow-back water volume accounts for less than fifty percent of theamount of injected water used for the fracturing operation. Theflow-back water stream also contains materials that are leached out ofthe shale formation such as bicarbonates, (e.g., nahcolities). Theflow-back water mixture also carries with it many volatile organiccompounds as well as the micro-organism debris, any dissolved salts orbrines, and a significant amount of the initially-injected proppant andtheir produced fines. Treatment and/or disposal of this flow-back aresignificant issues for the industry. For example, see Smyth, Julie Carr.(2012). Ohio quakes put pressure on use of fracturing. Associated Press.pp. D1, D6. Lowry, Jeff, et al. (2011 December). Haynesville trial wellapplies environmentally focused shale technologies. World Oil. pp.39-40, 42. Beckwith, Robin. (2010 December). Hydraulic Fracturing TheFuss, The Facts, The Future. JPT. pp. 34-35, 38-41. Ditoro, Lori K.(2011). The Haynesville Shale. Upstream Pumping Solutions. pp. 31-33.Walser, Doug. (2011). Hydraulic Fracturing in the Haynesville Shale:What's Different? Upstream Pumping Solutions. pp. 34-36. Bybee, Karen.(2011 March). In-Line-Water-Separation Prototype Development andTesting. JPT. pp. 84-85. Bybee, Karen. (2011 March).Produced-Water-Volume Estimates and Management Practices. JPT. pp.77-79. Katz, Jonathan. (2012 May). Report: Fracking to Grow U.S.Water-Treatment Market Nine-Fold by 2020. Industry Week. U.S. App. Pub.No. 2012/0012307A1; U.S. App. Pub. No. 2012/0024525A1; U.S. App. Pub.No. 2012/0070339A1; U.S. App. Pub. No. 2012/0085236A1; U.S. App. Pub.No. 2012/0097614A1. Each of the above references are incorporated hereinby reference for all purposes.

Currently, it is common practice to kill micro-organisms that are in thewater mixture, either initially or insitu, by chemical or other types ofbiocides, so that the gaseous and liquid hydrocarbons that are trappedin the oil shale's matrix formation can flow freely into the channelsand fissures vacated by the flow-back water mixture. Also, the channelscreated by the fracturing process must be kept open by the proppantsthat are initially carried into the fissures in the fracture zones bythe injected water mixture. If the micro-organisms are not killed theywill multiply, rapidly; and, if they remain in the fissures, they willgrow and reduce or entirely block the flow hydrocarbons from thesefissures. Another significant micro-organism type problem is thepossible presence of a strain of microbes that have an affinity forseeking out and digesting any free sulfur or sulfur bearing compoundsand producing hydrogen sulfides that must be removed from any productgas stream because it is a highly dangerous and carcinogenic material.All these types of micro-organisms must be destroyed if this type ofproblem is to be avoided.

In addition to the possibility of micro-organisms multiplying andblocking the flow of hydrocarbon product, the presence of dissolvedsolids in the water solution can also be a problem in the injected watermixture. They can deposit themselves as scale or encrustations in thesame flow channels and fissures. These encrustations, if allowed to bedeposited in these channels, will also reduce or block the flow ofhydrocarbons to the surface. In order to avoid this condition, attemptsare made in current industry practice to have the dissolved solidscoalesce and attach themselves to the suspended or other colloidalparticles present in the water mixture to be removed before injection inthe well; however, those efforts are only partly effective. See, e.g.Denny, Dennis. (2012 March). Fracturing-Fluid Effects on Shale andProppant Embedment. JPT. pp. 59-61. Kealser, Vic. (2012 April).Real-Time Field Monitoring to Optimize Microbe Control. JPT. pp. 30,32-33. Lowry, Jeff, et al. (2011 December). Haynesville trial wellapplies environmentally focused shale technologies. World Oil. pp.39-40, 42. Rassenfoss, Stephen.

(2012 April). Companies Strive to Better Understand Shale Wells. JPT.pp. 44-48. Ditoro, Lori K. (2011). The Haynesville Shale. UpstreamPumping Solutions. pp. 31-33. Walser, Doug. (2011). Hydraulic Fracturingin the Haynesville Shale: What's Different? Upstream Pumping Solutions.pp. 34-36. Denney, Dennis. (2012 March). Stimulation Influence onProduction in the Haynesville Shale: A Playwide Examination. JPT. pp.62-66. Denney, Dennis. (2011 January).

Technology Applications. JPT. pp. 20, 22, 26. All of the above areincorporated herein by reference for all purposes.

In recent years, the oil industry has tried to develop a number of waysto address these concerns. The use of ultra violet light in conjunctionwith reduced amounts of chemical biocide has proven to be only partiallyeffective in killing water borne micro-organisms. This is also true whenalso trying to use ultra-high frequency sound waves to killmicro-organisms. Both these systems, however, lack the intensity andstrength to effectively kill all of the water-borne micro-organisms withonly one weak short time residence exposure and with virtually noresidual effectiveness. Both systems need some chemical biocides toeffectively kill all the water borne micro-organisms that are in water.Also, some companies use low-frequency or low-strength electro-magneticwave generators as biocide/coalescers; however, these too have proven tobe only marginally effective.

Therefore, an object of further examples is to economically address andsatisfactorily resolve some of the major environmental concerns that areof industry-wide importance. Objects of still further examples are toeliminate the need for brine disposal wells, eliminate the use of toxicchemicals as biocides for micro-organism destruction, or for scaleprevention, and the recovery of all flow-back or produced water forreuse in subsequent hydraulic fracturing operations. Examples of theinvention provide technically sound and economically viable solutions tomany of the public safety issues that have concerned the industry inhydraulic fracturing.

SUMMARY OF EXAMPLES OF THE INVENTION

Advantages of various examples of the present invention include the needfor less (or no) disposal of brine water, since substantially alldissolved salts are coalesced and converted into suspended particlesthat are separated and incorporated with recovered proppant and finesfor inclusion in a feed material for fusion by pyrolysis in a rotarykiln. Similarly, examples of the invention eliminate the need forchemical biocides since the high intensity, variable, ultra-highfrequency electromagnetic wave generator kills the micro-organisms thatare present in water before water is injected into the formation. Theelectromagnetic wave also prevents the formation of scale encrustations;therefore, there is no need to add scale inhibitors to the fracturingwater mixture. As a result, substantially all the flow-back water from afracturing operation is reused with all the remaining solid materialsbeing recycled and reconstituted into appropriately-constituted andproperly sized proppants for subsequent use in fracturing operations. Inaddition, since volatile organic compounds are burned and vaporized,there is no need for any sludge or other types of solid waste disposalfacilities.

According to one aspect of the invention, a system for use in wellfracturing operations is provided, comprising: a first separatorincluding a slurry intake and a slurry output with a first watercontent; a second separator having a slurry input, positioned to receiveslurry from the slurry output of the first separator, and a slurryoutput with a second, lower water content; a kiln positioned to receivethe slurry output of the second separator and having an output; a quenchpositioned to receive slag from the output of the kiln; a crusherpositioned to receive quenched slag from the quench; a mill positionedto receive crushed material from the crusher; a first screen positionedto receive milled material from the mill, the size of the screen whereinthe size of the first screen determines the upper boundary of theproppant size; and a second screen positioned to receive material passedby the first screen, wherein the size of the second screen determinesthe lower boundary of the proppant size. In at least one example, thesystem further comprises a proppant storage silo positioned to receiveproppant from between the first and the second screens. In a furtherexample, the system also includes a blender positioned to receiveproppant from the silo. In a more specific example, the first separatorincludes a water output and the system further includes: a water storagetank positioned to receive water from the first separator, a biocidecoalescer positioned to receive water from the water storage tank, thecoalescer having an output feeding the blender, and at least onefracture pump receiving at least proppant and water from the blender,wherein the fracturing pump produces flow in water for well fracturingoperations.

According to a further example of the invention, a method is providedfor creating a proppant of a specific size from a slurry extracted froma fractured hydrocarbon well, the method comprising: separating waterfrom the slurry, resulting in a slurry stream and a liquid stream;mixing the slurry stream with particulate, resulting in a feed material;fusing proppant material in the feed material; quenching the fusedproppant material; breaking the fused proppant material; sizing thebroken material for the specific size; and mixing broken material thatis not of the specific size with the feed material. In some examples ofthe invention, the method further comprises extracting the slurry fromthe flow of produced fluid from a hydrocarbon well, wherein the producedfluid includes water and a slurry, wherein the separating of the slurryresults in at least two streams, wherein one of the at least two streamscomprises a substantially liquid stream of water and another of the atleast two streams comprises the slurry. Examples of acceptable means forseparating the slurry from a flow of produced fluid from a hydrocarbonwell include a conventional three-phase separator.

In at least one example, the mixing comprises: injecting the solidstream into a kiln; and injecting particulate into the kiln, wherein theinjection of the particulate changes the viscosity of a slaggingmaterial wherein the slagging material comprises the solid stream andthe injected particulate. In a further example, the injectingparticulate into the kiln is dependent upon the viscosity of theslagging material in the kiln wherein the injecting of the particulateis increased when the slagging material is too viscous for even flow inthe kiln. In some examples, the injecting of the particulate isdecreased when the slagging material viscosity is so low that the flowrate through the kiln is too fast for fusing of proppant material.

In a further example, the quenching comprises spraying the fusedproppant material with the liquid stream and the breaking comprises:crushing the quenched proppant material and grinding the crushedproppant material.

In still another example the sizing comprises screening and/orweight-separating.

In some examples, the fusing comprises heating the slagging materialwherein volatile components in the slagging material are released in agas phase and proppant material in the slagging material is fused. Insome such examples, the rate of flow of the fused material outputting akiln is measured, and the heating in the kiln is adjusted, based on themeasuring.

In yet another example, the method further includes separating theslurry from a flow of produced fluid from a hydrocarbon well, whereinthe produced fluid includes water and solids, wherein said separatingthe slurry results in at least two streams, and wherein one of the atleast two streams comprises a substantially liquid stream of water andanother of the at least two streams comprises the slurry. In at leastone such example, the method also includes imparting an electromagneticpulse to the substantially liquid stream of water, wherein proppant ismixed with the substantially liquid stream of water before or after theimparting.

According to a further aspect of the of the invention, a system isprovided for creating a range of proppant of specific sizes from aslurry extracted from a fractured hydrocarbon well, the systemcomprising: means for separating water from the slurry, resulting in aslurry stream and a liquid stream; means for mixing the slurry streamwith particulate, resulting in a feed material; means for fusingproppant material in the feed material; means for quenching the fusedproppant material; means for breaking the fused proppant material; meansfor sizing the broken material for the specific size; and means formixing broken material that is not of the specific size with the feedmaterial. In at least one example, the means for mixing broken materialthat is not of the specific size comprises the means for fusing.

An example of the means for separating includes at two-phase separationtank with a funnel at a lower end with a conduit leading to the input toan auger. A two-phase separation tank uses the principle ofgravity-precipitating unit (with or without baffles). An alternative toa gravity-precipitation unit is a pressurized tank from a hydroconesystem forcing slurry to a feed-hopper with an auger.

In a further example, the means for mixing the slurry stream withparticulate comprises: means for injecting the slurry stream into akiln; and means for injecting particulate into the kiln, wherein theinjection of the particulate changes the viscosity of a slaggingmaterial and wherein the slagging material comprises the slurry streamand the injected particulate. One example of useful a means forinjecting the slurry stream into the kiln include: an auger from themeans for separating to a kiln feed-hopper. As the auger advances theslurry stream toward the hopper more water comes off. Alternativesinclude a flight conveyor belt, a bucket conveying system, and othersthat will occur to those of skill in the art. Specific examples ofuseful means for injecting sand into the kiln include: a bucket-elevatorconveyor with a variable drive bringing particulate (e.g. sand) from asilo where the specified sand resides. The variable drive allowschanging of the amount of sand depending on the temperature measured atthe exit of the kiln. The temperature is related to viscosity. Forexample, as temperature varies around some set point of about 2200 F,feed of sand will be increased as temperature drops. It will bedecreased as temperature rises. In a more specific example, no changewill be made for a variation of about 5%, while, over 5%, the amount ofvariation will cause increase or decrease in an amount that is dependenton the particular kiln, proppant solid feed, and other conditions thatwill occur to those of skill in the art. Other examples of means forinjecting include a belt conveyor or flight conveyor and otherequivalents that will occur to those of skill in the art.

In a further example, the means for quenching comprises means forspraying the fused proppant material with the liquid stream that wasseparated from the slurry (e.g., with nozzles and/or a water wall). Afurther alternative for cooling the material would be air quenching. Inat least one example, the hot solids mixture from a kiln is depositedonto a moving, perforated steel conveyor belt, which is placed over awater collection pan. Water is applied to the mixture while on the belt.

In still a further example, the means for breaking comprises: means forcrushing the quenched proppant material; and means for grinding thecrushed proppant material. In one such example, the means for crushingcomprises a crusher having the following specifications: an eccentricgyratory crusher (conical) so that the crushing space can be varied toobtain various sizes. Alternative crushers include: jaw crushers, rollercrushers, ball crushers, and other equivalents that will occur to thoseof skill in the art. In some examples, the crusher reduces a solidified,agglomerated mixture into pieces having a size range of about ¼ inch toabout ½ inch.

In some examples, the means for grinding comprises a grinder of thefollowing type: a rod mill, a ball mill, an autogenous mill, bowl mill,and other equivalents that will occur to those of skill in the art. Inat least some such examples, crushed material is moved by conveyor anddischarged into a mixing/grinding unit where the materials are reducedin size; in at least one example, 98-99% of the material passes througha #30 sleeve opening of about 590 microns, and the passes material issimilar in size and strength to sharp, fine sand.

In some examples, the means for sizing comprises a screener having atleast one screen. An example of a screener that is acceptable is avibrating screen. If the material passes the screen, it is classified as“specification size.” If it is too small, it drops out to an undersizedfeed that is fed back to the input of the hopper of the kiln. If it istoo large, it is separated into an oversized feed that is provided tothe hopper at the input of the kiln. In at least one example, the overand undersized streams are combined before they are injected into thekiln. Other acceptable means for sizing includes fixed screens, rotatingscreens, and means for weight-separating (e.g., a cyclone through whichbroken material passes and/or specific gravity separation in liquidsolution). Examples of acceptable cyclones will occur to those of skillin the art. Another acceptable means for separating includes specificgravity separation in liquid solution. Acceptable separation systems ofthat type will occur to those of skill in the art.

According to a further example, the means for fusing comprises means forheating the slagging material wherein volatile components in theslagging material are released in a gas phase and proppant material inthe slagging material is fused. One example of such a means for heatingthe slagging material includes a slagging rotary kiln, an inclinedrotary kiln, and a horizontal kiln with both direct and indirect firingcapabilities. Alternative means for fusing proppant material in the feedmaterial include: a non-slagging kiln, a vertical furnace (e.g. aHershoff furnace, a Pacific, multi-hearth, vertical furnace), ahorizontal traveling grate sintering furnace, and other equivalents thatwill occur to those of skill in the art. In some examples, the kilnoperation involves feeding the slurry materials into the kiln and addingproppant to start the process of fusing the slurry material and proppanttogether into a flowing agglomerate material mass. As the mixture movesdown to the kiln discharge port, the temperature of the mixtureincreases due to the heat being generated by the kiln's burner. At thesame time, the viscosity of the mixture decreases as the temperatureincreases. During this same period of time, the organic materials whichare carried in the mixture are burned, vaporized, and discharged into avent stack, leaving a flowing solids material mixture. The viscosity ofthis flowing mixture is adjusted by either increasing or decreasing theheat released by the kiln's burner, or by adding more or less proppantto the mixture, or both.

Some examples of the invention also include means for measuring the rateof flow of the fused material outputting the kiln. Examples of means formeasuring the flow of the fused material outputting the kiln includes atemperature sensor providing a signal. Other equivalent means will occurto those of skill in the art. A means for adjusting the heating in thekiln based on the measuring is provided in still other embodiments.Examples of means for adjusting the heating in the kiln based on themeasuring include: changing the flow of proppant input into the kiln,based on the temperature measurement, and changing the rate of fuel flowto the kiln burner to increase or decrease the amount of heat beingreleased in the kiln.

As mentioned above, the separating of the slurry from the flow from awell results in at least two streams, wherein one of the at least twostreams comprises a substantially liquid stream of water. And, in astill more detailed example, a means for imparting an electromagneticpulse to the substantially liquid stream of water is provided. At leastone example of a means for imparting an electromagnetic pulse to thesubstantially liquid stream of water is disclosed in U.S. Pat. No.6,063,267, incorporated herein by reference for all purposes.Alternatives to the device described in that patent for use in variousexamples of the present invention include: traditionalbiocide/coalescers (chemical, electrical, and mechanical) as will occurto those of skill in the art.

In at least one example, the specific pulse imparted has the followingcharacteristics: variable, ultra-high frequencies in the range ofbetween about 10 and 80 kHz. Other pulses having sufficient frequency tokill the micro-organisms present in water and to cause dissolved solidsto coalesce will occur to those of skill in the art and may depend onthe specific properties of the water at a particular well. The pulsewill generally rupture the cells of the micro-organisms.

In still a further example of the invention, a means for mixing proppantwith the substantially liquid stream of water is provided (for mixingeither before or after the imparting). Examples of means for mixingproppant with water included a blender as will occur to those of skillin the art (for example, a screen or open, grated tank). In someexamples, surface tension reducing agents are also added in the blender,as are other components that will occur to those of skill in the art.The mixture is then provided to a means of increasing the pressure ofthe mixture (e.g., a fracturing pump—aka “intensifier unit”—as willoccur to those of skill in the art) and the pressurized mixture isinjected into a well.

In still further examples, proppant is made to specific sizes fromproduced and/or flow-back water, as well as other sources, using acombination of a kiln, crusher, mill, and screens, to produce proppantof various sizes that those of skill in the art will recognize as beingdesirable in fracturing operations. See, e.g., Mining Engineering,“Industrial Materials”, pp. 59-61, June 2012 (www.miningengineeringmagazine.com), incorporated herein by reference. The various sizes aremade by adjusting the mill and screens used.

In still another example, a method is provided for treating hydrocarbonwell fracture water (which includes both “flow back” and “produced”water) from a hydrocarbon well, wherein the method comprises: separatingsolids from fracture water, wherein a flow of water with suspendedsolids results; separating the flow of water into a plurality of flowsof water; generating positive charge in the plurality of flows of water,wherein a plurality of flows of positively-charged water results;comingling the plurality of flows of positively-charged water after saidgenerating. In a further example, the method also comprises: monitoringan oil/water interface level and controlling the oil/water interfacelevel in the separator.

In a more specific example, method further comprises slowing the flowrate in the plurality of flows of water to be less than the flow rate ofthe flow of water with suspended solids. Slowing the flow rate allowsfor greater residence time during the step of generating positivecharge. That increases the amount of positive charge in the water whichis considered to be beneficial for killing microbes in the water and forproviding residual positive charge for a period of time when the waterhas been injected into a geologic formation from which hydrocarbons areto be produced. The presence of positive charge in the water geologicformation is believed to have benefits in reducing the presence ofvarious flow-reducing structures in the formation.

In a further specific example the method generating positive charge inthe flows of water comprises treating each of the plurality of flows ofwater with electromagnetic flux.

In still a further example, the majority of the suspended solids areless than about 100 microns. In some such examples, substantially allthe suspended solids are less than about 100 microns. In a more limitedset of examples, the majority of the suspended solids are less thanabout 10 microns. And in still a more limited set of examples,substantially all the suspended solids are less than about 10 microns.By reducing the size of the suspended solids, it becomes possible topass the water through devices that are practical for generatingpositive charge in the water at a reasonable cost by using, for example,stainless steel conduits when the suspended solids approach 100 micronsand softer materials (for example, PVC) as the solids approach 10microns and smaller.

And some further examples, the separating comprises two-stageseparating. In at least one such example, two-stage separatingcomprises: passing the fracture water through a three-phase separator,wherein a water output from the three-phase separator results, andpassing the water output from the three-phase separator through atwo-phase separator. In at least one such method, the three-phaseseparator comprises a four-material separator having at least fouroutputs including: a slurry, water having suspended solids therein,hydrocarbon liquid, and hydrocarbon gas.

According to another example of the invention, a system is provided fortreating hydrocarbon well fracture water from a hydrocarbon well, systemcomprising: means for separating solids from fracture water, wherein aflow of water with suspended solids results; means for separating theflow of water into a plurality of flows of water; means for generatingpositive charge in the plurality of flows of water, wherein a pluralityof flows of positively-charged water results; and means for cominglingplurality of flows of positively-charged water.

In at least one such system, the means for separating comprises athree-phase, four material separator. For example, and a more specificexample, the means for separating further comprises a second two phaseseparator, the two-phase separator comprising an input for receivingwater flow from the three-phase gas oil separator, and an output for theflow of water with suspended solids. In a further example, there is alsoprovided: means for monitoring an oil/water interface level; and meansfor controlling the oil/water interface level in the first and secondseparator. In one such example, the means for monitoring comprises anoil/water interface level indicator and control valve sensor (forexample, a cascade control system).

In some examples, the means for separating the flow of water into aplurality of flows of water comprises a manifold having an input port toreceive the flow of water with suspended solids and a plurality ofoutput ports, each of which has a cross-sectional area that is smallerthan the cross-sectional area of the input of the manifold; and whereinthe sum of the cross-sectional areas of the output ports is greater thanthe cross-sectional area of the input ports, whereby the flow rateexiting the manifold is less than the flow rate entering the manifold.In at least one example, the manifold comprises a 1:12 manifold (forexample, having cross-sectional diameters of 4 inches in the outputports and a larger cross sectional diameter in the input ports). In analternative example, the means for separating the flow of water into aplurality of flows of water comprises a water truck having a pluralityof compartments, each compartment being positioned to receive a portionof the flow of water.

In a further example, the means for generating positive charge comprisesmeans for treating each of the plurality of flows of water withelectromagnetic flux. At least one such example, the means for treatingeach of the plurality of flows of water with electromagnetic fluxcomprises: a pipe; and at least one electrical coil having an axissubstantially coaxial with the pipe. In some such examples, the pipeconsists essentially of non-conducting material. In some such examples,the pipe consists essentially of stainless steel. In a variety ofexamples, there is also provided a ringing current switching circuitconnected to the coil. In some such examples, the ringing currentswitching circuit operates in a full-wave mode at a frequency betweenabout 10 kHz to about 80 kHz.

In still a further example, the means for co-mingling comprises amanifold having input ports for a plurality of flows ofpositively-charged water and an output port. In one such example, themeans for co-mingling further comprises a well fracturing water andproppant blender. In a variety of examples, the majority of thesuspended solids are less than about 100 microns. In some such examplessubstantially all the suspended solids are less than about 100 microns.In a more limited set of examples, the majority of the suspended solidsare less than about 10 microns. In an even more limited set of examples,substantially all the suspended solids are less than about 10 microns.

In a more specific example, the means for separating comprises atwo-stage separator. In one such example, the two-stage separatorcomprises: a three-phase separator having a water output coupled to aninput of a two-phase separator. In a further example, three-phaseseparator comprises a four-material separator having at least fouroutputs including: a slurry, water having suspended solids therein,hydrocarbon liquid, and hydrocarbon gas.

In another example of the invention, a system is provided for treatmentof hydrocarbon well fracture water, the system comprising: a multi-phaseseparator; a manifold having an input port connected to an output of themultiphase separator and having multiple output ports; a plurality ofpipes, each having coils wound on the pipe, wherein each pipe has aninput end connected to an output port of the manifold and each pipe hasan output end; a co-mingling manifold having input ports connected tothe output ends of the plurality of pipes.

In at least one such system, a proppant-water blender is also providedthat is connected to an output of the co-mingling manifold.

In at least one such system, the multi-phase separator comprises amulti-stage separator. In a more specific example, the multi-stageseparator comprises a two-stage separator, wherein: a first stage of thetwo-stage separator comprises a three-phase separator and a second stageof the two-stage separator comprises a two-phase separator. In an evenmore specific example, the three-phase separator comprises afour-material separator including an oil-water interface control system.

In still another example of the invention, a method is provided forcontrolling of water/liquid hydrocarbon interface in a three-phaseseparator, the method comprising: establishing a water/liquidhydrocarbon interface in a three-phase separator; measuring thewater/liquid hydrocarbon interface in the three-phase separator, whereina water/liquid hydrocarbon interface measurement signal results;comparing the water/liquid hydrocarbon interface measurement signal to aset point, wherein a comparison signal results; reducing the flow-backor produced water into the three-phase separator of hydrocarbon wellfracture water when the comparison signal indicates the water/liquidhydrocarbon interface is above the set point; and increasing flow intothe three-phase separator when the comparison signal indicates thewater/liquid hydrocarbon interface is below the set point, wherein theincreasing flow comprises hydrocarbon well fracture water from a welland make-up water from a storage tank or a lagoon.

In a further example, the method also comprises: decreasing the flowexiting the three-phase separator at the same rate in balance with theflow as it decreases into the three-phase separator, and increasing theflow exiting the three-phase separator at the same balanced rate as theflow increases into the three-phase separator.

In another example, a system is provided for controlling of water/liquidhydrocarbon interface in the three-phase separator, where in the systemcomprises: means for establishing a water/liquid hydrocarbon interfacein a three-phase separator; means for measuring the water/liquidhydrocarbon interface in the three-phase separator, wherein awater/liquid hydrocarbon interface measurement signal results; means forcomparing the water/liquid hydrocarbon interface measurement signal to aset point, wherein a comparison signal results; means for reducing theflow into the three-phase separator of hydrocarbon well fracture waterwhen the comparison signal indicates the water/liquid hydrocarboninterface is above the set point and for increasing flow into thethree-phase separator when the comparison signal indicates thewater/liquid hydrocarbon interface is below the set point, wherein theincreasing flow comprises hydrocarbon well fracture water and make-upwater.

In at least one example, the means for establishing a water/liquidhydrocarbon interface comprises a diaphragm wier. In a further example,the means for measuring the water/liquid hydrocarbon interface comprisesa liquid level indicator controller-type sensor. In still a furtherexample, comparing the water/liquid hydrocarbon interface measurementsignal to a set point comprises a continuous capacitance leveltransmitter.

In some examples, the means for reducing and for increasing the flowinto the three-phase separator comprises a turbine type flow meter andan inlet type control valve in-line with the input of the three-phaseseparator.

In further examples, also provided are: means for decreasing andbalancing the flow exiting the three-phase separator at the same rate asthe flow decreases into the three-phase separator and for increasing theflow exiting the three-phase separator at the same balanced rate as theflow increases into the three-phase separator.

In at least one such example the means for decreasing and increasing theflow exiting the three-phase separator comprises a flow-type meterconnected in-line with the water output of the three-phase separator. Inanother example, the means for decreasing and increasing the flowexiting the three-phase separator comprises an orifice-type flowcontroller controlling the water output of the three-phase separator.

Examples of the inventions are further illustrated in the attacheddrawings, which are illustrations and not intended as engineering orassembly drawings and are not to scale. Various components arerepresented symbolically; also, in various places, “windows” intocomponents illustrate the flow of material from one location to another.However, those of skill in the art will understand which components arenormally closed. Nothing in the drawings or detailed description shouldbe interpreted as a limitation of any claim term to mean something otherthan its ordinary meaning to a person of skill in the varioustechnologies brought together in this description.

DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram of a well site showing the flow of various materialsused in various examples of the invention.

FIGS. 2A and 2B, when connected along their respective dotted lines, area side view of an example of the invention.

FIG. 2A1 is an alternative to the embodiment of FIG. 2A.

FIG. 2C is a schematic of a control system used in at least one exampleof the invention.

FIGS. 3A and 3B, when connected by the overlapping components next totheir dotted lines, are a plan view of the example of FIGS. 2A and 2B.

FIGS. 3C and 3D are an isometric and side view, respectively, of anaspect of the examples of FIGS. 2A-2B and FIGS. 3A-3B.

FIG. 4 is a side view of a further example of the invention.

FIG. 5 is a plan view of the example of FIG. 4.

FIG. 6 is a diagram of a well site showing the flow of various materialsused in various examples of the invention.

FIG. 7 is a diagram of a well site showing the flow of various materialsused in various examples of the invention.

FIG. 8 is a top view of an example of the invention.

FIG. 9 is a side view of an example of the invention.

FIG. 10A is a side view of support leg 100 of FIG. 8.

FIG. 10B depicts a top view of foot 101 of FIG. 10A.

FIG. 11 is a cross section view taken through line A of FIG. 9.

FIG. 12 is a cross section view taken along line C of FIG. 8.

FIG. 13 is a cross section view taken along line B of FIG. 8.

FIG. 14A is a top view of a component of an example of the invention.

FIG. 14B is a section view of the component of FIG. 14A.

FIG. 15 is a schematic of a control system useful in examples of theinvention.

FIG. 16 is a representational view of a system useful in examples of theinvention.

FIG. 17 is a schematic of a control system useful according to examplesof the invention.

FIG. 18 is a perspective view of examples of the invention.

FIG. 19 is a perspective view of an apparatus embodying the invention.

FIG. 20 is an exploded view of the pipe unit of the apparatus of FIG.19.

FIG. 21 is a longitudinal cross sectional view taken through the pipeunit of FIG. 19.

FIG. 22 is a simplified circuit diagram of the pipe unit of FIG. 19.

FIG. 23 is a detailed schematic diagram of the electrical circuit of thepipe unit of FIG. 19.

FIG. 24 is a diagram showing certain wave shapes produced by the pipeunit of FIG. 19 during operation.

FIG. 25 is a circuit diagram similar to FIG. 4 but showing a modifiedembodiment of the invention.

FIG. 26 is a view similar to FIG. 21 but showing a modified embodimentof the invention in which the pipe unit has only one coil surroundingthe liquid flow pipe.

FIG. 27 is a detailed circuit diagram similar to FIG. 23 but showing anelectrical circuit for use with the pipe unit of FIG. 27.

FIG. 28 is a chart specifying presently preferred values of certainparameters of the apparatus of FIGS. 19 to 24.

DETAILED DESCRIPTION OF EXAMPLES OF THE INVENTION

Referring now to FIG. 1, a flow diagram of the use of the invention in ahydrocarbon well having a well bore 1 with cemented casing 3 passingthrough fracture zones that are isolated by packers. Coil tubing 9 isinserted by rig 11 for fracture operations known to those of skill inthe art.

Flow back (and/or produced) water is routed to three-phasesolids/liquids/gas/hydrocarbon/water separator 10, from which anyhydrocarbon liquids and gases are produced, and water from separator 10is routed to a fracturing-water storage tank 17 which may also includewater from another source (aka “make up” water). Wet solids are passedfrom three-phase separator 10 to two-phase separator 14, which produceswater that is passed to a quench system 32 and slurry that are passed tokiln 24. Slag is passed from kiln 24 through quench system 32 to crusher40 and then to mill 46. Milled material is separated into a specifiedsize at screen 50 that is sent to a proppant storage silo 26, which mayalso include proppant from another source (e.g., a supplier of sand).Water is provided to biocide/coalescer unit 13. Proppant provided toblender 15 from silo 26, water is supplied to blender 15 frombiocide/coalescer unit 13; the blended water and proppant are thenprovided to fracturing pumps 19, which pumps the blend into the wellwhere it fractures the oil shale layer 21. Other additives may beprovided to the blender 15, as desired. Also, proppant may be added tothe water before the biocide/coalescer unit 13 in alternative examples.

Examples of the invention create a range of proppants of specific sizesfrom a slurry extracted from a hydraulically-fractured hydrocarbon well.

In FIGS. 2A and 2C and in FIGS. 3A-3D, a more specific example is seen.In that example, a slurry is extracted from gravity-precipitated slurrythat accumulates at the bottom of a conventional three-phase separationtank 10 (which is of a common design known to those of skill in theart). In the specific example of FIG. 2A, as will occur to those ofskill in the art, a water/liquid hydrocarbon interface level facilitatesthe separation and recovery of any liquid hydrocarbon product from theflow back or produced water stream (which is under pressure as it entersseparator 10) by means of an internally or externally mounted waterlevel indicator (not shown). That indicator sends a water levelmeasurement signal to a pre-programmed, low level/high level water flowcontrol data integrator (not shown). When the water level in theseparator 10 reaches the high level set point, the data integratoractuates a control valve (not shown) that controls flow through thewater feed pipe 10 a (labeled “Inlet Water”) to reduce the amount ofwater going into the three phase separator, and the rate of flowcontinues to decrease until a point is reached where the incoming amountof water equalizes and balances out the volume of water being withdrawnfrom the three phase separator. Conversely, if the water level in thethree phase separator 10 falls below the low level set point, the dataintegrator actuates and further opens up the control valve in inlet pipe10 a in order to increase the amount or rate of water flow that issufficient to stabilize the interface level. If this additional amountof water is not sufficient to stabilize the water level at the interfacelevel, the integrator actuates a pump (not shown) and opens up anothercontrol valve (not shown) which is located in a discharge pipe (notshown) in water storage tank 17 (FIG. 1). That discharge pipe isconnected to the inlet pipe 10 a; thus water from fracturing waterstorage tank 17 continues to flow into the three phase separatortogether with the flow back or produced water until the water level inthe separator 10 reaches the proper interface level. Then, the make-upwater control valve closes and the make-up water pump is shut off. Thiscontrol sequence is necessary in order to achieve steady state andcontinuous operational stability in the separation and recovery of anyliquid hydrocarbon product that is carried into the three phaseseparator by the flow back or produced water feed stream.

A weir and baffle configuration (commonly known in gas/oil separationunits) facilitates the separation and recovery of the liquid hydrocarbonproduct, if any, by using the interface level as the maximum height ofthe water in the separator and allowing the lighter liquid hydrocarbonsto float on top of the water layer and then be withdrawn as liquidhydrocarbon product after it flows over the liquid hydrocarbon productweir and is withdrawn at the hydrocarbon liquid product outlet flangeconnection. A horizontal baffle under the weir limits the amount ofpotential water carry over that might be comingled with the liquidhydrocarbon product stream. As the flow back or produced water streamenters the three phase separator 10 the depressurization releases thelighter hydrocarbon gases and their release assists in the flotation ofthe liquid hydrocarbon products as well as the release of the gaseoushydrocarbon products through outlet 10 c. Water flows out of separator10 through pipe 10 b to a surge tank (not shown) and is then pumped backto water tank 17 (FIG. 1).

From separator 10, a motor-driven positive displacement diaphragm-typesludge pump 12 moves the slurry upwards to the inlet opening of atwo-phase water/solids separation tank 14 resulting in a solid stream 16and a liquid stream 18 that is pumped by pump 19 to a quench (labeled“Q”). From the bottom of the two-phase water/solids separation tank 14,a bucket-elevator conveyor 20 transports the precipitated slurrymaterials from the lower part of the water/solids separation tank 14upwards from the water level and discharges them into the feed-hopper 22(FIG. 2B). The discharge is seen in FIG. 2A as going over a dashed line,which connects with the dashed line to the left of FIG. 2B where slurryis seen accumulating in feed-hopper 22 of a slagging, rotary-kiln 24,leaving the slurry water to remain in the water/solids separation tank14 and the elevator 20. As a result, all separation is carried out atatmospheric pressure rather than in pressurized-vessels (as is currentpractice).

In the feed-hopper 22, the slurry materials from the water/slurryseparation tank are mixed with specification proppant from silo 26 (FIG.1), as well as under-sized and over-sized solid materials that come froma final screening unit 50 (described below).

As the fusion process for the proppant material proceeds, inorganicproppant materials are fused into a uniform mass and volatile organicmaterials that may have been present in the feed stream from thewater/solids separation tank 14 are burned and vaporized prior to thegases being eventually discharged into an exhaust vent 30.

The proppant material exiting from the rotary kiln 24 is quenched with astream of water to reduce the temperature of the material, as it emergesfrom the outlet of the kiln 24. In some examples, discharged materialflows onto a perforated, motor-driven stainless-steel conveyor belt 35and the water cascades, through spray nozzles 34 on to the moving belt35 thereby solidifying and cooling the proppant material. The water usedfor quenching the proppant material comes from the water/solidsseparation tank 14 (see FIG. 2A) using, e.g., a motor-driven centrifugalpump 19 to push the water to the quench nozzles 34 of FIG. 3B. An excesswater collection pan 36 is positioned under the conveyor belt 35 tocollect and recover any excess quench water and convey it back to thewater/solids separation tank 14 by a motor-driven centrifugal pump 21and a pipeline shown flowing to return “R” of FIG. 2A.

Quenching the hot proppant material, as it is discharged from the kiln24, causes a multitude of random, differential-temperature fractures orcracks due to the uneven contraction of the proppant material and thehigh internal stresses caused by rapid quenching. The different sizedpieces of proppant material are discharged directly into the materialcrusher 40.

Crushing or breaking up the large irregular pieces of proppant materialand reducing their size is accomplished, in some examples, by amotor-driven, vertical-shaft, gyratory, eccentric cone or jaw crusher,known to those of skill in the art. The degree of the size reduction isadjusted by changing the spacing or crusher gap, thus allowing a rangeof different material sizes to be produced, as is known to those ofskill in the art.

Sizing of the proppant material is accomplished by the grinding ormilling of the crushed proppant material after the proppant material isdischarged at the bottom of the crusher. In the illustrated example, thematerial is conveyed upwards to ball mill 46 by a bucket-elevatorconveyor 44. In at least one alternative example, a rod mill is used.The mill 46 is adjusted to grind the proppant material to differentspecific size ranges by changing rotation, the size and spacing of therods or balls in the mill 46 (or its rotation).

The milled proppant material flows by gravity down through the grindingzone of the mill and is discharged onto vibrating screen 50 where themesh openings are selectively sized to a specific sieve value. Forexample, for soft mineral shale the mesh openings are in the 590 micronrange or a #30 sieve. For hard mineral shale (for example) the meshopenings would be in the 150 micron range or a #100 sieve. Proppantmaterial of the proper size flows downward by gravity through aselectively sized screen exiting at “A.” Proppant material that is toolarge to pass through the slanted, vibrating screen 53 exits onto belt51 a (seen better in FIG. 3B), and the rest drops to screen 55. Proppantmaterial between the sizes of screens 53 and 55 exit as correctly sizedproppant at “A” and is transported to silo 26 (FIG. 1). Under-sizedproppant drops onto belt 51 a which conveys the under-sized andover-sized proppant to belt 51 b, which then carries the proppant backto kiln 24, through elevator 25. FIGS. 3A and 3B illustrate a top viewof an example of the invention in which the components are mounted on atrailer or skid mounted that are assembled at a well site with biocideand other components (e.g., FIGS. 4 and 5). Such trailers or skids areleveled in some examples by leveling jacks 81.

As seen in FIGS. 3C and 3D, elevator 25 deposits material into the topof feed hopper 22 and elevator 23 deposits material from the silo intofeed hopper 22 from a lower level through an opening in feed hopper 22.

The properly-sized proppant materials flow is fed, by gravity, into aspecification proppant container (not shown) for transfer to thespecification proppant storage silo 26 (FIG. 1) which may also containspecification proppant from another source.

Referring now to FIG. 2B, it is desirable to control the viscosity ofthe proppant feed mixture, to attain stability of sustaining an optimumfusion temperature (in some examples, approximately 2200 degreesFahrenheit). As the proppant feed mixture temperature is rising, due tothe heat in kiln 24, the process of fusing the various inorganicmaterials into a uniformly viscous mass is achieved when the temperaturein the proppant mixture reaches the fusion temperature of silicondioxide or sand. The viscosity of the proppant material is a function ofthe temperature of the material itself Such control is accomplished invarious ways.

In at least one example, the temperature of the fused material ismeasured, by any means know to those of skill in the art, for example,an optical pyrometric sensor in quench system 32, as it exits from thekiln. If the temperature is above the fusion point of the material, itwill be too liquid, and the fuel to the kiln is reduced. At the sametime, more specification proppant may be added to the feed hopper 22.This affects the temperature because the material coming from the slurryis not uniform and is not dry; adding proppant from the silo evens outthe variability.

Referring now to FIG. 2C, a schematic is seen in which sensor 67 signalsintegrator 69 with the temperature of the output of the kiln 24.Integrator 69 then controls variable-speed motor 90 (FIG. 3A) thatoperates elevator 23 (see also FIG. 3B) that carries proppant from thebottom of proppant silo 26 and discharges it into the slagging rotarykiln feed-hopper 22. The different material streams are comingled in thefeed-hopper 22 before they enter the revolving drum of the kiln 24. Theproportion or amount of specification proppant that is needed to beadded to the material stream from the water/solids tank 14 is adjusted,depending upon the changes in the composition of the materials comingfrom the water/solids separation tank 14. This increases uniformity ofthe proppant material feed mixture that kiln 24 uses in the fusionprocess. In at least one example, if the temperature is too high, thefuel to the burner is reduced; if that does not correct it, the amountof proppant to the kiln will be increased. Likewise, if the temperatureis too low, the fuel is increased to the burner; and, if that does notwork, the amount of proppant is decreased. Alternative arrangements willoccur to those of skill in the art.

Referring back to FIG. 2C, integrator 69 also controls valve 63 toincrease or decrease the supply of fuel 61 for kiln burner 65.

Referring again to FIG. 1, one example of the invention is seen in whichseparator 10 is seen feeding the slurry to separator 14, and water fromseparator 10 is the joined with new “make-up” (in tank 17) water to beused in injection in a new fracturing job. The combined flows aretreated by an electromagnetic biocide/coalescer 13 of the type describedin U.S. Pat. No. 6,063,267,incorporated herein by reference for allpurposes (commercially available as a Dolphin model 2000), which is set,in at least one example, to impart an electro-magnetic pulse having thefollowing characteristics: selectable, variable, and tuneablefrequencies in a range between about 10-80 KHz. Such a pulse issufficient to kill biological organisms and to cause a positive chargeto be applied to the water, making the dissolved solids capable of beingprecipitated or coalesced in the well.

FIGS. 4 and 5 are side and top views, respectively, of an exampletrailer-mounted or skid-mounted system that includes a set ofbiocide/coalescers 70 a-70 l, organized to receive fracturing tank waterin the type of flow rate used in common shale-fracture operations. Suchunits are run from an electrical control panel 72, that is connected toan overhead power and control distribution rack 73 that connects tooverhead power feed components 71 a-71 l. Power is supplied by an engine75 that turns an electrical generator 77 that is connected to power feed79 for supplying power in a manner known to those of skill in the art.

Referring now to FIG. 2A1, an alternative to the embodiment of FIG. 2Aas seen in which the water level of two-phase separator 14 is at thesame as the level and three-phase separator 10. In such an embodiment,there is fluid communication through a diaphragm pump 12 and tanks areat atmospheric pressure such that the liquid gas interface is at thesame level.

Referring now to FIG. 6, according to another example of the invention,a system is provided for treating hydrocarbon well fracture water from ahydrocarbon well, system comprising a means for separating solids fromfracture water comprising a three-phase, four material separator 10,wherein a flow of water with suspended solids results that is passed toa fracturing water storage tank 17. From there so-called “make-up water”may be added to fracture water storage tank 17 and the flow of water ispassed through a means for separating the flow of water into a pluralityof flows of water (described in more detail below); to a means forgenerating positive charge in the plurality of flows of water (forexample, a set of biocide coalescers or units as described above),wherein a plurality of flows of positively-charged water results. Ameans for comingling plurality of flows of positively-charged water moreevenly distributes the positive charge in the water before it is passedto blender 15 for use in subsequent well fracturing operations.

FIG. 7 illustrates an example in which the means for separating furthercomprises a second stage, two-phase separator 14, the two-phaseseparator comprising an input for receiving water flow from thethree-phase gas oil separator. The water flow from the three-phaseseparator is taken from the midsection of the separator, while mostsolids dropped out at the bottom, as described above. However, the waterfrom the three-phase separator includes suspended solids that can damagea biocide coalesce or unit. Accordingly, in one example embodiment, thewater flow from the three-phase separator 10 is passed to the input of atwo-phase separator 14, which also includes an output for the flow ofwater with suspended smaller suspended solids. Two-phase separator 14also drops solids out of its lower section in the form of a slurry. Theslurry from three-phase separator 10 and two-phase separator 14 arefurther processed (for example as described above) or disposed of insome other manner.

Referring now to FIGS. 8 and 9, an example of a three-phase,four-material separator 90, useful according to some embodiments of theinvention and place of three-phase separator 10, as seen. Separator 90and includes an input 92, a slurry output 94, a liquid hydrocarbonoutput 98 and a gas output 80. As also seen in FIG. 10A, separator 90 issupported by legs 100 (which includes a foot 101, as seen in FIG. 10B)welded to the side of separator 90.

Referring again to FIG. 9, as well as FIG. 11 (which is a cross sectiontaken through line A of FIG. 9) and FIG. 13 (which is a cross-sectionaltaken along line B of FIG. 8), a baffle 111 allows water having somesuspended solids to exit separator 90 while larger solids exit as theslurry at the bottom exit 94. FIG. 12 illustrates a cross-section ofinput 92 (taken along line C of FIG. 8) where input pipe 92 is supportedby support 120 connected to the bottom of separator 90 and holding inputpipe 92 and a saddle.

In a further example, there is also provided: means for monitoring anoil/water interface level; and means for controlling the oil/waterinterface level in the first and second separator. In one such example,the means for monitoring comprises an oil/water interface levelindicator and control valve sensor (for example, a cascade controlsystem).

As illustrated in FIG. 18, in some examples, the means for separatingthe flow of water into a plurality of flows of water comprises amanifold 181 having an input port valve 183 to receive the flow of waterwith suspended solids from a means for separating and a plurality ofoutput ports attached to biocide coalescer units 184, each output porthaving a cross-sectional area that is smaller than the cross-sectionalarea of the input of the manifold. In some examples, the sum of thecross-sectional areas of the output ports is greater than thecross-sectional area of the input ports, whereby the flow rate exitingthe manifold is less than the flow rate entering the manifold. In atleast one example, the manifold 181 comprises a 1:12 manifold (forexample, having cross-sectional diameters of 4 inches in the outputports and a larger cross sectional diameter in the input ports). In analternative example, the means for separating the flow of water into aplurality of flows of water comprises a water truck as is known in theart (not shown) having a plurality of compartments, each compartmentbeing positioned to receive a portion of the flow of water. Inoperation, water passes through valve 183 into manifold 181 and the flowis slowed as it is separated into parallel flows through theparallel-connected biocide coalescer units 184 to increase residencetime for imparting electromagnetic flux in order to maximize thepositive charges the electromagnetic flux imparts to the water. Theoutput of the units 184 is comingled in manifold 186, who's output iscontrolled by valve 188. The entire assembly of the manifolds andbiocide coalescer units is, in some examples, mounted on frame 184 whichmay be lifted by harness 186 onto a pad at a well site or onto the bedof a truck for transportation.

In a further example, the means for generating positive charge comprisesmeans for treating each of the plurality of flows of water withelectromagnetic flux. At least one such example is seen in FIGS. 19-28,where the means for treating each of the plurality of flows of waterwith electromagnetic flux comprises: a pipe and at least one electricalcoil having an axis substantially coaxial with the pipe. In some suchexamples, the pipe consists essentially of non-conducting material. Insome such examples, the pipe consists essentially of stainless steel. Ina variety of examples, there is also provided a ringing currentswitching circuit connected to the coil. In some such examples, theringing current switching circuit operates in a full-wave mode at afrequency between about 10 kHz to about 80 kHz. Specifically, stillreferring to FIGS. 19-28, turning first to FIG. 19, an apparatusembodying the invention is indicated generally at 910 and comprisesbasically a pipe unit 912 and an alternating current electrical powersupply 914. The pipe unit 912 includes a pipe 916 through which liquidto be treated passes with the direction of flow of liquid beingindicated by the arrows A. The pipe 916 may be made of variousmaterials, but as the treatment of the liquid effected by the pipe unit912 involves the passage of electromagnetic flux through the walls ofthe pipe and into the liquid passing through the pipe, the pipe ispreferably made of a non-electrical conducting material to avoiddiminution of the amount of flux reaching the liquid due to some of theflux being consumed in setting up eddy currents in the pipe material.Other parts of the pipe unit 912 are contained in or mounted on agenerally cylindrical housing 918 surrounding the pipe 916.

The pipe unit 912 is preferably, and as hereinafter described, onedesigned for operation by a relatively low voltage power source, forexample, a power source having a voltage of 911 V(rms) to 37 V(rms) anda frequency of 60 Hz and, therefore, the illustrated power supply 914 isa voltage step down transformer having a primary side connected to aninput cord 920 adapted by a plug 922 for connection to a standard mains,such as one supplying electric power at 120 V 60 Hz or 240 V 60 Hz, andhaving an output cord 924 connected to the secondary side of thetransformer and supplying the lower voltage power to the pipe unit 912.The pipe unit 912 may be designed for use with pipes 916 of differentdiameter and the particular output voltage provided by the power source914 is one selected to best suit the diameter of the pipe and the sizeand design of the related components of the pipe unit.

The pipe unit 912, in addition to the housing 918 and pipe 916, consistsessentially of an electrical coil means surrounding the pipe and aswitching circuit for controlling the flow of current through the coilmeans in such a way as to produce successive periods of ringing currentthrough the coil means and resultant successive ringing periods ofelectromagnetic flux passing through the liquid in the pipe 916. Thenumber, design and arrangement of the coils making up the coil means mayvary, and by way of example in FIGS. 20 and 21 the coil means is shownto consist of four coils, L₁, L₂-outer, L₂-inner and L₃ arranged in afashion similar to that of U.S. Pat. No. 5,702,600, incorporated hereinby reference for all purposes. The coils, as shown in FIGS. 20 and 21,are associated with three different longitudinal sections 926, 928 and930 of the pipe 916. That is, the coil L₁ is wound onto and along abobbin 932 in turn extending along the pipe section 926, the coil L₃ iswound on and along a bobbin 934 itself extending along the pipe section930, and the two coils L₂-inner and L₂-outer are wound on a bobbin 936itself extending along the pipe section 928, with the coil L₂-outerbeing wound on top of the coil L₂-inner. The winding of the two coilsL₂-inner and L₂-outer on top of one another, or otherwise in closeassociation with one another, produces a winding capacitance betweenthose two coils which forms all or part of the capacitance of a seriesresonant circuit as hereinafter described.

Referring to FIG. 20, the housing 918 of the pipe unit 912 is made up ofa cylindrical shell 938 and two annular end pieces 940 and 942. Thecomponents making up the switching circuit are carried by the end piece940 with at least some of them being mounted on a heat sink 944 fastenedto the end piece 940 by screws 946. In the assembly of the pipe unit912, the end piece 940 is first slid onto the pipe 916, from the rightend of the pipe as seen in FIG. 20, to a position spaced some distancefrom the right end of the pipe, and is then fastened to the pipe by setscrews 948. The three coil bobbins 932, 936 and 934, with their coils,are then moved in succession onto the pipe 916 from the left end of thepipe until they abut one another and the end piece 940, with adhesiveapplied between the bobbins and the pipe to adhesively bond the bobbinsto the pipe. An annular collar 950 is then slid onto the pipe from theleft end of the pipe into abutting relationship with the coil L₃ and isfastened to the pipe by set screws 960, 960. The shell 938 is then slidover the pipe and fastened at its right end to the end piece 940 byscrews 962, 962. Finally, the end piece 942 is slid over the pipe 916,from the left end of the pipe, and then fastened to the shell 938 byscrews 964 and to the pipe by set screws 966.

The basic wiring diagram for the pipe unit 912 is shown in FIG. 22. Theinput terminals connected to the power source 914 are indicated at 968and 970. A connecting means including the illustrated conductorsconnects these input terminals 968 and 970 to the coils and to theswitching circuit 972 in the manner shown with the connecting meansincluding a thermal overload switch 974. The arrow B indicates theclockwise direction of coil winding, and in keeping with this referencethe coil L₃ and the coil L₂-outer are wound around the pipe 916 in theclockwise direction and the coils L₁ and L₂-inner are wound around thepipe in the counterclockwise direction. Taking these winding directionsand the illustrated electrical connections into account, it will beunderstood that when a current i_(c) flows through the coils in thedirection indicated by the arrows C, the directions of the magneticfluxes passing through the centers of each of the coils, and thereforethrough the liquid in the pipe, are as shown by the arrows E, F, G and Hin FIG. 22. That is, the fluxes passing through the centers of the coilsL₁, L₂-inner and L₃ move in one direction longitudinally of the pipe andthe flux passing through the center of the coil L₂-outer moves in theopposite direction. Depending on the design of the switching circuit972, it may be necessary or desirable to provide a local ground for theswitch circuit 972 and when this is the case, the switching circuit maybe connected with the input terminals 968 and 970 through an isolationtransformer 976, as shown in FIG. 22.

FIG. 23 is a wiring diagram showing in greater detail the connectingmeans and switching circuit 972 of FIG. 22. Referring to FIG. 23, theswitching circuit 972 includes a 12 V power supply subcircuit 976, acomparator subcircuit 978, a timer subcircuit 980, a switch 982 and anindicator subcircuit 984.

The components D2, R5, C5, R6 and Z1 comprise the 12 V DC power supplysubcircuit 976 which powers the other components of the trigger circuit.Resistors R1 and R2 and the operational amplifier U1 form the comparatorsubcircuit 978. The resistors R1 and R2 form a voltage divider thatsends a signal proportional to the applied AC voltage to the operationalamplifier U1. The capacitor C1 serves to filter out any “noise” voltagethat might be present in the AC input voltage to prevent the amplifierU1 from dithering. The amplifier U1 is connected to produce a “low”(zero) output voltage on the line 986 whenever the applied AC voltage ispositive and to produce a “high” (+12 V) output when the AC voltage isnegative.

When the AC supply voltage crosses zero and starts to become positive,the amplifier U1 switches to a low output. This triggers the 555 timerchip U2 to produce a high output on its pin 93. The capacitor C2 and R3act as a high-pass filter to make the trigger pulse momentary ratherthan steady. The voltage at pin 92 of U2 is held low for about one-halfmillisecond. This momentary low trigger voltage causes U2 to hold asustained high (+12 V) on pin 93.

The switch 982 may take various different forms and may be a sub-circuitconsisting of a number of individual components, and in all events it isa three-terminal or triode switch having first, second and thirdterminals 988, 990 and 992, respectively, with the third terminal 992being a gate terminal and with the switch being such that by theapplication of electrical signals to the gate terminal 992 the switchcan be switched between an ON condition at which the first and secondterminals are closed relative to one another and an OFF condition atwhich the first and second terminals are open relative to one another.In the preferred and illustrated case of FIG. 23, the switch 982 is asingle MOSFET (Q1). The MOSFET (Q1) conducts, that is sets the terminals988 and 990 to a closed condition relative to one another, as soon asthe voltage applied to the gate terminal 992 becomes positive as aresult of the input AC voltage appearing across the input terminals 968and 970 becoming positive. This in turn allows current to build up inthe coils L₁, L₂-inner, L₂-outer, and L₃. When the time constant formedby the product of the resistor R4 and the capacitor C3 has elapsed, the555 chip U2 reverts to a low output at pin 93 turning the MOSFET (Q1) toits OFF condition. When this turning off of (Q1) occurs, any currentstill flowing in the coils is diverted to the capacitance which appearsacross the terminals 988 and 990 of (Q1). As shown in FIG. 23, thiscapacitance is made up of the wiring capacitance C_(c) arisingprincipally from the close association of the two coils L₂-inner andL₂-outer. This winding capacitance may of itself be sufficient for thepurpose of creating a useful series resonant circuit with the coils, butif additional capacitance is needed, it can be supplied by a separatefurther tuning capacitor (C_(t)).

When the switch (Q1) turns to the OFF or open condition, any currentstill flowing in the coils is diverted to the capacitance (C_(c) and/orC_(t)) and this capacitance in conjunction with the coils and with thepower source form a series resonant circuit causing the current throughthe coils to take on a ringing wave form and to thereby produce aringing electromagnetic flux through the liquid in the pipe 916. Byadjusting the variable resistor R4, the timing of the opening of theswitch (Q1) can be adjusted to occur earlier or later in each operativehalf cycle of the AC input voltage. Preferably, the circuit is adjustedby starting with R4 at its maximum value of resistance and then slowlyadjusting it toward lower resistance until the LED indicator 994 of theindicator subcircuit 984 illuminates. This occurs when the peak voltagedeveloped across the capacitance (C_(c) and/or C_(t)) exceeds 150 V atwhich voltage the two Zener diodes Z2 can conduct. The Zener diodescharge capacitor 962 and the resulting voltage turns on the LED 994.When this indicator LED lights, the adjustment of the resistor R4 isthen turned in the opposite direction until the LED just extinguishes,and this accordingly sets the switch (Q1) to generate a 150 V ringingsignal.

FIG. 24 illustrates the function of the circuit of FIG. 23 by way ofwave forms which occur during the operation of the circuit. Referring tothis Figure, the wave form 996 is that of the AC supply voltage appliedacross the input terminals 968 and 970, the voltage being an alternatingone having a first set of half cycles 998 of positive voltagealternating with a second set of half cycles 900 of negative voltage.The circuit of FIG. 23 is one which operates in a half wave mode withperiods of ringing current being produced in the coils of the pipe unitonly in response to each of the positive half cycles 998. The wave form902 represents the open and closed durations of the switch (Q1), andfrom this it will be noted that during each positive half cycle 998 ofthe supply voltage the switch (Q1) is closed during an initial portionof the half cycle and is opened at a time well in advance of the end ofthat half cycle (with the exact timing of this occurrence beingadjustable by the adjustable resistor R4).

The opening and closing of the switch (Q1) produces the current waveform indicated at 904 in FIG. 24 which for each positive half cycle ofthe supply voltage is such that the current through the coils increasesfrom zero during the initial portion of the half cycle, during which theswitch (Q1) is closed, and then upon the opening of the switch (Q1) thecurrent rings for a given period of time. The voltage appearing acrossthe coils of the pipe unit is such as shown by the wave form 906 of FIG.24, with the voltage upon the opening of the switch (Q1) taking on aringing shape having a maximum voltage many times greater than thevoltage provided by the power supply 914.

The frequency of the ringing currents produced in the coils and of theringing voltages produced across the coils can be varied by varying thecapacitance (C_(c) and/or C_(t)) appearing across the switch (Q1) and ispreferably set to be a frequency within the range of 10 kHz to 80 kHz.

Parameters of the apparatus of FIGS. 19-24, including nominal pipe size,arrangement of coils in terms of number of turns, gage and length,tuning capacitor capacitance and associated nominal power supply voltageare given in the form of a chart in FIG. 28.

As mentioned above, the switching circuit illustrated and described inconnection with FIGS. 22, 23 and 24 is one which is operable to produceone period of ringing current and ringing voltage for each alternatehalf cycle of the applied supply voltage. However, if wanted, theswitching circuit can also be designed to operate in a full wave modewherein a period of ringing current and of ringing voltage is producedfor each half cycle of the supply voltage. As shown in FIG. 25, this canbe accomplished by modifying the circuit of FIG. 22 to add a secondswitching circuit 908 which is identical to the first switching circuit972 except for facing current wise and voltage wise in the oppositedirection to the first circuit 972. That is, in FIG. 25 the firstcircuit 972 operates as described above during each positive half cycleof the applied voltage and the second circuit 908 operates in the sameway during the negative half cycles of the applied voltage, and as aresult, the number of periods of current and voltage ringing over agiven period of time is doubled in comparison to the number of periodsproduced in the same period of time by the circuit of FIG. 22.

Also, as mentioned above, the number of coils used in the pipe unit 912may be varied and if wanted, the pipe unit 912 may be made with only onecoil without departing from the invention. FIGS. 26 and 27 relate tosuch a construction with FIG. 26 showing the pipe unit to have a singlecoil 910 wound on a bobbin 912 and surrounding the pipe 916. Theswitching circuit used with the single coil pipe unit of FIG. 26 isillustrated in FIG. 27 and is generally similar to that of FIG. 23except, that because of the single coil 910 producing no significantwiring capacitance, it is necessary to provide the tuning capacitor(C_(t)) across the first and second terminals 988 and 990 of the switch(Q1). Further, since the coil means is made up of the single coil 910and located entirely on one side of the switch (Q1), it is unnecessaryto provide the isolation transformer 976 of FIG. 23 to establish a localground for the components of the switching circuit.

In still a further example, seen in FIG. 18 means for co-minglingcomprises a manifold 186 having input ports for a plurality of flows ofpositively-charged water from multiple means for generating positivecharge 184 and an output port connected to valve 188 directing an outputflow of water having positive charges therein to a blender for use inwell fracturing operations. In a variety of examples, the majority ofthe suspended solids are less than about 100 microns. In some suchexamples substantially all the suspended solids are less than about 100microns. In a more limited set of examples, the majority of thesuspended solids are less than about 10 microns. In an even more limitedset of examples, substantially all the suspended solids are less thanabout 10 microns.

Referring now to FIGS. 16 and 17, a system is shown for controlling ofwater/liquid hydrocarbon interface in the three-phase separator, wherein the system comprises: means for establishing a water/liquidhydrocarbon interface in a three-phase separator; means for measuringthe water/liquid hydrocarbon interface in the three-phase separator,wherein a water/liquid hydrocarbon interface measurement signal results;means for comparing the water/liquid hydrocarbon interface measurementsignal to a set point, wherein a comparison signal results; means forreducing the flow into the three-phase separator of hydrocarbon wellfracture water when the comparison signal indicates the water/liquidhydrocarbon interface is above the set point and for increasing flowinto the three-phase separator when the comparison signal indicates thewater/liquid hydrocarbon interface is below the set point, wherein theincreasing flow comprises hydrocarbon well fracture water from andmake-up water.

In at least one example, best seen in FIGS. 14A and 14B, the means forestablishing a water/liquid hydrocarbon interface comprises a diaphragmwier 140, and, ideally, the oil-water interface is established at thewier-bottom 140 b. Controlled by flow meters and control valves seen inFIGS. 15 and 16.

Referring now to FIG. 17, a more detailed example is seen of theinterface level control of a three phase, four material separator isprovided. As seen in the Figure, inlet flow of flow-back water to theseparator is measured by turbine meter (FE-101)/transmitter (FT-101) andcontrolled by flow control valve (FV-101) via flow controller (FIC-101).Make-up water inlet flow is measured by orifice plate (FE-103)/dPtransmitter (FT-103) and controlled by flow control valve (FV-103) viaflow controller (FIC-103). Water outflow is measured by orifice plate(FE-102)/dP transmitter (FT-102) and controlled by flow control valve(FV-102) via flow controller (FIC-102). The oil and water interfacelevel in the separator is measure by magnetic level gauge (LG-100) andalso by continuous capacitance level transmitter (LT-100). Both leveldevices are mounted on an external level bridle made up of 2 inchdiameter pipe. The bridle comprises manual valves (HV-1, HV-2, HV-3,HV-4, HV-5, HV-6, HV-9, and HV-10) for maintenance on the bridle andattached instrumentation as will occur to those of skill in the art.HV-1 and HV-2 are used to isolate the bridle from the process. HV-3 andHV-4 are used to drain and vent the bridle respectively. HV-5 and HV-6are used to isolate the level gauge from the process. HV-9 and HV-10 areused to isolate the level transmitter chamber from the process. Eachinstrument on the bridle is equipped with valves for maintenance. HV-7and HV-8 are a part of the level gauge and are used to drain and ventthe level gauge respectively. HV-11 is a part of the level transmitterchamber and is used to drain the chamber.

The water/liquid hydrocarbon interface (aka “oil/water interface”) levelin the separator is maintained by level controller (LIC-100) withcascade control to flow-back inlet flow controller (FIC-101), make-upwater inlet flow controller (FIC-103) and water outflow controller(FIC-102). Cascade control is accomplished by the level controllersending a remote set point (RSP) to the associated flow controllers andresetting their set points to maintain interface level.

All controllers are set for steady state condition to maintain normalliquid level (NLL=50%). Set points for individual controllers aredetermined by desired capacity and separator sizing.

In one operational example, as the interface level increases, the levelcontroller resets the water outflow controller to throttle open whileresetting the flow-back inlet flow controller to throttle back tomaintain normal liquid level. An high liquid level (HLL=80%) alarm istriggered from an interface level transmitter analog signal to anoperator, allowing the operator should take appropriate actions toregain control of the interface level or operating conditions.

As interface level decreases, the level controller resets the wateroutflow controller to throttle back while the resetting flow-back inletflow controller to throttle open to maintain normal liquid level. Ifinterface level decreases to a low liquid level (LLL=10%), the systemplaces the make-up water flow controller on cascade control from theinterface level controller by software switch LX-100.

It should be kept in mind that the previously described embodiments areonly presented by way of example and should not be construed as limitingthe inventive concept to any particular physical configuration. Changeswill occur to those of skill in the art from the present descriptionwithout departing from the spirit and the scope of this invention. Eachelement or step recited in any of the following claims is to beunderstood as including to all equivalent elements or steps. The claimscover the invention as broadly as legally possible in whatever form itmay be utilized. Equivalents to the inventions described in the claimsare also intended to be within the fair scope of the claims. Allpatents, patent applications, and other documents identified herein areincorporated herein by reference for all purposes.

What is claimed is:
 1. A method of treating hydrocarbon well fracturewater from a hydrocarbon well, said method comprising: separating solidsfrom fracture water, wherein a flow of water with suspended solidsresults; separating the flow of water into a plurality of flows ofwater; generating positive charge in the plurality of flows of water,wherein a plurality of flows of positively-charged water results;comingling the plurality of flows of positively-charged water after saidgenerating.
 2. A method as in claim 1, further comprising: monitoring anoil/water interface level and controlling the oil/water interface levelin the separator.
 3. A method as in claim 1, further comprising slowingthe flow rate in the plurality of flows of water to be less than theflow rate of the flow of water with suspended solids.
 4. A method as inclaim 1, wherein said generating positive charge in the flows of watercomprises treating each of the plurality of flows of water withelectromagnetic flux.
 5. A method as in claim 1, wherein the majority ofthe suspended solids are less than about 100 microns.
 6. A method as inclaim 5, wherein substantially all the suspended solids are less thanabout 100 microns.
 7. A method as in claim 5, wherein the majority ofthe suspended solids are less than about 10 microns.
 8. A method as inclaim 1, wherein said separating comprises two-stage separating.
 9. Amethod as in claim 8, wherein said two-stage separating comprises:passing the fracture water through a three-phase separator, wherein awater output from the three-phase separator results, and passing thewater output from the three-phase separator through a two-phaseseparator.
 10. A system for treating hydrocarbon well fracture waterfrom a hydrocarbon well, a system comprising: means for separatingsolids from fracture water, wherein a flow of water with suspendedsolids results; means for separating the flow of water into a pluralityof flows of water; means for generating positive charge in the pluralityof flows of water, wherein a plurality of flows of positively-chargedwater results; and means for comingling plurality of flows ofpositively-charged water.
 11. A system as in claim 10, wherein saidmeans for separating comprises a three-phase, four material separator.12. A system as in claim 11, wherein said means for separating furthercomprises a second two phase separator, the two-phase separatorcomprising an input for receiving water flow from the three-phase gasoil separator, and an output for the flow of water with suspendedsolids.
 13. A system as in claim 11, further comprising: means formonitoring an oil/water interface level; and means for controlling theoil/water interface level in the first and second separator.
 14. Asystem as in claim 10, wherein the means for separating the flow ofwater into a plurality of flows of water comprises a manifold having aninput port to receive the flow of water with suspended solids and aplurality of output ports, each of which has a cross-sectional area thatis smaller than the cross-sectional area of the input of the manifold;and wherein the sum of the cross-sectional areas of the output ports isgreater than the cross-sectional area of the input ports, whereby theflow rate exiting the manifold is less than the flow rate entering themanifold.
 15. A system as in claim 10, wherein the means for separatingthe flow of water into a plurality of flows of water comprises a watertruck having a plurality of compartments, each compartment beingpositioned to receive a portion of the flow of water.
 16. A system as inclaim 10, wherein said means for generating positive charge comprisesmeans for treating each of the plurality of flows of water withelectromagnetic flux.
 17. A system as in claim 16, wherein the means fortreating each of the plurality of flows of water with electromagneticflux comprises: a pipe; and at least one electrical coil having an axissubstantially coaxial with the pipe.
 18. A system as in claim 10,wherein said means for co-mingling comprises a manifold having inputports for a plurality of flows of positively-charged water and an outputport.
 19. A system as in claim 18, wherein said means for co-minglingfurther comprises a well fracturing water and proppant blender.
 20. Asystem as in claim 10, wherein the majority of the suspended solids areless than about 100 microns.
 21. A system as in claim 20, whereinsubstantially all the suspended solids are less than about 100 microns.22. A system as in claim 21, wherein the majority of the suspendedsolids are less than about 10 microns.
 23. A system as in claim 10,wherein said means for separating comprises a two-stage separator.
 24. Asystem as in claim 23, wherein said two-stage separator comprises: athree-phase separator having a water output coupled to an input of atwo-phase separator.
 25. A system for treatment of hydrocarbon wellfracture water, the system comprising: a multi-phase separator; amanifold having an input port connected to an output of the multiphaseseparator and having multiple output ports; a plurality of pipes, eachhaving coils wound on the pipe, wherein each pipe has an input endconnected to an output port of the manifold and each pipe has an outputend; a co-mingling manifold having input ports connected to the outputends of the plurality of pipes.
 26. A system as in claim 25, furthercomprising a proppant-water blender connected to an output of theco-mingling manifold.
 27. A system as in claim 25, wherein themulti-phase separator comprises a multi-stage separator.
 28. A system asin claim 27, wherein the multi-stage separator comprises a two-stageseparator, wherein: a first stage of the two-stage separator comprises athree-phase separator and a second stage of the two-stage separatorcomprises a two-phase separator.
 29. A system as in claim 28, whereinthe three-phase separator comprises a four-material separator.
 30. Asystem as in claim 29, wherein the four-material separator comprises anoil-water interface control system.